Pivotable thrust vectoring transom panel

ABSTRACT

A transom flap can be deployed from the transom of an amphibious vehicle when the vessel is water borne. The transom flap is pivotally mounted and can be extended to extend into a position relatively acute to the transom of the vessel the transom flap can be extended to impinge the propulsion jet of a jet propulsion drive system of the vessel or it can be deployed to extend out of the jet stream but at a less acute angle such that it will be helpful in trim adjustment of the vessel at speed.

This application is a continuation of application Ser. No. 08/595,943,filed Feb. 6, 1996, now U.S. Pat. No. 5,579,711.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention has to do with amphibious craft having the capability totravel on land and on sea. The invention pertains to a pivoting transomor ramp having multiple pivoting sections, one section of which is usedwhen the craft is operating as a watercraft to enhance the vehicle trimcapabilities and pitch control of the craft as it is underway and waterborne.

A transom flap or transom panel is deployable such that it performsfunctions related to the trim of the craft. Trim control is important inplaning modes of operation as well as during the time when the craft isaccelerating to planing speed.

2. Description of the Prior Art

It is well know in prior art to use trim tabs and other related transommounted panel and planing devices on watercraft to assist in adjustingthe trim of the vessel along its minor axis by controlling the lift atthe stem of the boat. Such trim tabs are known to enhance theperformance of the watercraft by raising or lowering the bow of thecraft to achieve optimum boat speed. This is beneficial in attainingmaximum boat speed as well as maximum hull efficiency. The dragreduction resulting from the use of trim tabs is the primary benefit oftheir use however trim tabs also result in a smoother ride and areduction of water spray generated by the hull.

Trim tabs, mounted to the stem of the host craft, rely solely on boatspeed to generate the lift needed to affect the trim of the vessel. Atspeed the trim tabs may allow the host watercraft to attain speeds thatexceed the fundamental hull speed of the boat.

It has been known to use a waterjet nozzle mounted jet stream deflectorfor trim control. Waterjet mounted trim control systems requiresignificant hardware, i.e. pumps, motors and plumbing to be effective.The complexity and increased waterjet length of prior art devices isinefficient when compared to the thrust vectoring embodiment of theinvention disclosed herein.

SUMMARY OF THE INVENTION

This invention is a flap or panel that is used on the hinged transomdoor or ramp of an amphibious vehicle. The transom or ramp is hinged atthe base and is normally held in an upright and locked position when thecraft is water borne. The transom flap or panel however is in a deployedposition such that it extends outwardly from the transom door or ramp ata nominal right angle when the watercraft is being accelerated or is atspeed in the water.

The transom flap is adjustably mounted by means of a hinge connection atthe bottom of the transom flap and a supporting hydraulic or pneumaticactuating cylinder intermediate the top and bottom of the transom flap.

The adjustability of the transom flap will allow it to be moved tovarious positions ranging from either a fully extended cylinder rodposition to a position where the propulsion stream of water, referred toas "waterjets" herein, used to drive the vehicle impinges against theinterior surface of the panel to thereby affect the trim of the vesselto raise its bow. The transom flap presented here can generate liftingforce similar to the force generated by trim tabs and the transom flapscan generate down force independent of watercraft speed by vectoringwaterjet thrust up.

One of the advantages of the invention is that the transom flap has theability to vector the propulsor or waterjet thrust up and provide liftfor planing. It should be pointed out that the pair of waterjets used bythe watercraft are the primary propulsion force used to propel thewatercraft when water borne.

One of the objects of the invention is to provide control of bow plow-inwhile operating the watercraft as a displacement craft at speeds greaterthan fundamental hull speed. Another object is to provide pitch controlto compensate for varying sea conditions by up-vectoring the waterjetthrust to raise the bow and operate without taking water over the bow.

One further object of the invention is to provide increased planingsurface area to the vessel by means of the deployable transom flap whilealso increasing lift at the stern of the craft through the use of a liftenhancing wedge at the trailing end of the transom flap.

Another object of the invention is to provide a ballistic barrier in theramp of an amphibious vehicle to enhance protection when the craft isoperating on land.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is clearly set out in the drawing figures in which:

FIG. 1 is a side elevation view of the vessel incorporation the transomflap which is shown in a partially extended deployment;

FIG. 2 is the same view as FIG. 1 but showing the transom flap extendedout of the path of the propulsion stream;

FIG. 3 is a representation of a transom door and the transom flap showndeployed away from the door;

FIG. 4 is a view from the rear of the vessel showing the transom flapdeployed as it would be when the vessel is at sea.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention can be most easily envisioned when looking at FIG. 3 incombination with FIG. 1.

FIG. 1 shows the vessel, generally 10, which includes a hull 12, a bowportion 14 and a stern portion 16 as is usual for water craft. Thevessel shown is an amphibious craft that is equipped with tracks forsupporting and driving the vehicle on land surfaces and is equipped witha water jet propulsion drive for propelling the vessel when the craft iswater borne.

The invention is housed in, or more properly, is a part of, the transomor ramp 18 which is pivotally connected for instance at pivot point 20to the hull of the craft 12. The transom or ramp 18 is pivotallylowerable about the pivot point provided to provide man access to theinterior of the craft and to allow quick loading and unloading. Intransport modes both on land and in water the transom or ramp may bepositively latched in a closed position as shown in FIGS. 1, 2 and 3.

The transom may include doors such as 22 and 24 to allow access tocompartments behind these doors. A frame such as 26 defines a cavity inthe transom or ramp where the transom flap will be stowed when thetransom or ramp is closed and the vehicle is operating on land. Insidethe cavity defined by frame 26 there is formed a second cavity 28,bounded at an end thereof which includes a hydraulic cylinder stabilizercollar 30, into which a hydraulic cylinder will be stowed when thetransom flap is closed.

The hydraulic actuator 32 includes a rod portion 34 that is extendiblein a known manner into and out of the hydraulic cylinder 36. Thehydraulic actuator would be pivotally mounted at the upper end thereof,38, through a bracket (not shown) to the frame 26 of the transom orramp. The rod end of the hydraulic actuator would be pivotally mountedby means of a lug to the interior side of the transom flap at the pivotpoint provided by tab arrangement 42. A rod accommodating cutout 44 in araised portion 46 of the interior of the transom flap allows the transomflap to be pivoted to a deployment more than generally a right anglefrom the transom. The preferred embodiment for the actuator ishydraulically controlled actuation however other types of actuators,such as pneumatic actuators are contemplated by the inventor.

The raised portion 46, for filling a propulsor opening or port in thetransom or ramp, is stepped up from the normal surface 48 of theinterior of the transom flap. A hydraulic actuator accommodating recess40 is formed on the interior surface of the transom flap to accommodatethe hydraulic cylinder when the transom flap is stowed in the closedtransom or ramp when the vessel is in the on-land operating mode.

The obverse side of the transom flap is a generally flat ballisticsurface. It may include a lift enhancing or lift increasing wedgeportion 50 at the relative upper end thereof used to enhance thetrimming effect by increasing the lift of the transom flap when thetransom flap is deployed to a water contacting condition.

The preferred embodiment of a transom flap is not as wide as the widthof the vehicle. It has been found that a narrow transom flaps which arebetween fifty and eighty percent of the width of the vehicle are betterperformers then full width transom flaps. The width ratio of the transomflap to hull width is about fifty five percent in the preferredembodiment shown.

Turning now to FIGS. 1, 2 and 4 the propulsion jets, the up-vectoringaspect of the jet thrust, and the method by which the transom flap isused to trim the vessel and provide pitch control when at sea will bedescribed.

In FIG. 4 one port for the exhaust of the propulsion jet is shown asitem 52. A second propulsion waterjet port is shown as 54. A highpressure stream of water, shown as 52a in FIGS. 1 and 2 will be drivenout these outlet ports to drive and provide propulsive force to move thevessel, generally 10, through the water. Reference numeral 56 indicatesthe lower hull surface of the hull 12. The lower hull surface is theexterior surface that provides the main planing surface of the vesselwhen on the water. Items 58a and 58b shown in FIG. 4 are the coveredtracks of the vehicle. The vehicle tracks are covered with generallysmooth surfaced panels when the craft is operating as a watercraft.

In FIG. 2 the hydraulic actuator, comprised of the cylinder 32 and therod 34, is extended such that the transom flap, generally 60, ispositioned to be below the water propulsion jet 52a. In this deploymentthe surface 62 will impact on the water flowing off the surface 56 ofthe lower hull and will cause the bow 14 of the vessel to be loweredwith the goal being that the vessel will level out on a plane as soon aspossible after acceleration on the water. Once the vessel is on a planethe transom flap will be adjusted by means of the hydraulic actuator totrim the vessel for optimum speed on the water and at a maximizedefficiency for that particular speed.

In Fig. 1 the deployment of the transom flap, generally 60, is such thatit will allow the inboard surface 48 of the transom flap to contact thewaterjet 52a as shown. In this displacement the waterjet acting on thesurface will cause pressure build up on the transom flap and the bow ofthe craft will be raised higher out of the water. As the transom flap israised even higher thereby decreasing the angle between the transom flapand the transom the bow will be raised more. This transom flapdisplacement will be helpful in shifting the horizontal attitude orpitch of the watercraft when the vessel is accelerating up to planingspeed. Generally, once the vessel approaches planing speed the transomflap will be adjusted for optimum trim and it is expected that thewaterjet will no longer need to contact the inner surface of the transomflap.

The foregoing description, when read in conjunction with a perusal ofthe drawing figures, shows how the implementation of a wide, deepadjustable transom flap can be and is used to met the objects of theinvention. The following claims seek to protect the inventor's idea byclaiming the transom flap principle in a manner that captures the spiritof the invention. Minor deviations and nuances of the invention arecontemplated as being covered by the following claims.

What is claimed is:
 1. A transom flap for use on an amphibious vesselcomprising:a transom having at least a single port through said transom;said transom flap pivotally attached to said transom capable ofsubstantially closing said port, said transom flap further being capableof deployment to a position extending outwardly from said hull structureto open said port; waterjet propulsion system carried by said vessel,said system having at least a single waterjet propulsion outlet directedto deliver water through said port of said transom; means to positionsaid transom flap to impinge said waterjet and deflect said waterjetfrom its normal path, whereby said impingement of said waterjet on saidtransom flap will cause an attitude change in said vessel controllableby the degree of incidence said transom flap presents to said waterjet.2. The invention in accordance with claim 1 wherein said transom flappivotally connected to said transom is pivoted by means of actuatormeans connected to said vessel and to said transom flap.
 3. Theinvention in accordance with claim 2 wherein said transom flap is atleast fifty percent as wide as said hull of said vessel.
 4. Theinvention in accordance with claim 1 wherein said transom flap has asurface obverse to the surface said waterjet may impinge upon, saidobverse surface having a tab means for improving lift of said transomflap when said transom flap is deployed to a position wherein said tabcan contact the surface of the water supporting said vessel.
 5. Theinvention in accordance with claim 1 wherein impingement of saidwaterjets on said transom flap impingement surface will result in trimadjustment of said vessel.
 6. The invention in accordance with claim 5wherein a pair of waterjets are used to propel said vehicle.
 7. Theinvention in accordance with claim 6 wherein propulsion by a singlewaterjet on said impingement surface of said transom flap will result ina rotational movement about the major axis of said vessel as well as atorsional movement transverse to said major axis of said vessel.
 8. Theinvention in accordance with claim 1 wherein said transom flap obversesurface is a ballistic surface.